Doesn't have to be that difficult or perfect. I've used an old cooler with a piece of glass from a screen door for years. The first old cooler started falling apart, probably from the excessive heat, but a new old cooler was waiting to take its place. Solar wax melters aren't used for a very large portion of the year and while I'd love to have a really nice big one, I cannot justify the cost when my crude, mostly scrounged, cooler does the job so well.

Take a piece of 1/4 inch screening and put it over a plastic container then put the comb on a piece of paper towel on the screening. Once the wax melts the towel will act as a filter and keep the crud out of the melted wax. I use a styrofoam coolr with a piece of plexiglass glued over an opening cut in the lid. It works great.

I run it all through screening and then filter through paper towel on a second pass. Between those first two passes I'll let it sit and wash off any honey that is on it. I'll do successive runs through the melter until the sun bleaches the wax to my liking.